29.1 File

A company manufactures injection pumps for diesel engines. The file INJECTION.MTW contains data on the lifetime (in hours) of 40 injection pumps.

A first approximation to the analysis of these data is obtained by drawing a histogram:

nc29uf001.eps

The data do not follow a normal distribution, which is somehow expected, as these data refer to lifetimes of equipment. Probably an exponential or Weibull distribution can be fit to these data.

Focus now in the case of complete data (the failure times of all elements are known) or in the case of right censored data (it is known that some elements have lasted more than a certain time, because when the experiment ended they were still functioning).

nc29uf002.eps

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